Was just in Vienna last month too.
Before that was in Istanbul. Standing at the old city walls of Constantinople I teared up. Could just imagine that horrible day in 1453...
The single combats of the heroes of history or fable amuse our fancy and engage our affections: the skilful evolutions of war may inform the mind, and improve a necessary, though pernicious, science. But in the uniform and odious pictures of a general assault, all is blood, and horror, and confusion nor shall I strive, at the distance of three centuries, and a thousand miles, to delineate a scene of which there could be no spectators, and of which the actors themselves were incapable of forming any just or adequate idea.
Gibbon, Chapter 68
Of course, Gibbon does describe the progress of the siege and the actions and results of the assault in considerable detail. Still, this remark about the lack of spectators is what stuck in my memory.